This proposal addresses the design and manufacture of an innovative assay system to markedly improve the Membrane Filtration (MF) approach to microbiological sample analyses. The MF method is widely used in healthcare-related testing for identification and enumeration of cultured organisms as colony-forming-units. Our approach reduces the sample preparation time, minimizes risks of incidental sample contamination or cross-contamination between multiple sample setups, and reduces the volume of plastic disposables associated with each assay. The novel assay approach utilizes an enclosed filter cartridge through which a fluid sample is drawn, organisms captured, rinsed, media introduced, incubated, and colony forming units (cfu) analyzed after outgrowth. - All these steps are performed without opening the device, or involving any manipulations to transfer the harvested membrane sample from a filtration unit to another vessel for its culture and analysis. The new MF assay approach is enabled by a special cartridge design used in conjunction with an innovative vacuum system to overcome limitations of current membrane filtering devices. The fundamental approach has been demonstrated with small filter cartridges. The overall R&D task is to develop the approach for practical application in a larger format MF assay device to be consistent with current practice, i.e. 47 mm filters in a clearly visible, easily examined membrane surface. The research plan investigates means to scale up the assay system to larger devices. New prototypes will be fabricated and evaluated for performance. They will be compared with conventional MF assay preparations to confirm that microbial growth and the efficiency of colony identification and counting is equivalent to existing methodology. PUBLIC HEALTH RELEVANCE: This project develops an improved laboratory method for conducting microbial assays using the Membrane Filtration (MF) technique. The MF method is extensively used in public healthcare-related testing for identification and enumeration of bacteria.